The present invention generally relates to a lifting system in a limp aerostat. The lifting system is particularly suitable for the troposphere. It has a primary and secondary enclosure within a single envelope with each enclosure containing gas compositions that operate independently of each other for controlling lift.
A previous system of maintaining a limp aerostat within the troposphere relies on the release of ballast by night and lifting gas by day. The altitude varies over a wide range. The flight endurance of this system is limited by the need to dump about 15 percent of the gas and ballast during each 24 hour period. An alternate method is to use a taut aerostat which seeks out an altitude where the atmospheric density equals that of the aerostat. This requires strong fabric. Moreover, a small pin hole leak will result in considerable loss of lift over a period of days and will result in flight termination. Ice accumulation can sink the aerostat even more rapidly.